Please for the love of god do not disable the Google SafeBrowsing preferences. SafeBrowsing protects you from a lot of malicious websites, and does not leak much information to Google. For most people the security benefits of SafeBrowsing far outweigh the privacy concerns.
I would never disable it for my mom, or any non technical friends. But I would hope the majority of HN users are pretty good at spotting, and steering clear of malicious websites.
They're designed to trick you, so I don't think any population, no matter how sophisticated, should trust themselves to correctly identify malicious websites 100% of the time.
Additionally, some sites may potentially contain exploits that run as soon as you visit the site (vulnerabilities in plugins like Java or Flash, drive-by downloads, etc.) in which case it doesn't matter if you correctly identify the website as malicious and hit the "Back" button - it's already too late. Much better to avoid loading the content at all, which is exactly what is achieved with SafeBrowsing.
Safebrowsing protects you from more than tricky websites - it blocks sites and services that are known to serve malware. It doesn't matter how clever a user you are, if your browser (doesn't matter which one) navigates to a site that hosts malicious code that targets an unpatched vulnerability, you're hosed.
I would never disable it for my mom, or any non technical friends. But I would hope the majority of HN users are pretty good at spotting, and steering clear of malicious websites.